The invention relates to T.V. special effects generation and more particularly to the production of special television effects using digital techniques.
There is a continuing requirement for electronic special effects generation for use on air or on post production within the television environment.
A processor has already been described in U.S. Pat. No. 4,163,249 which is capable of altering the linear dimensions of the television picture to effect a `zoom` in or out of the picture in real time. This allows the rectangular picture to be made into a smaller or bigger rectangle relative to the normal frame size.
The present invention incorporates a modification of the processing system of the above to allow for a change in linear dimensions as the subject matter is zoomed.
This effect is intended to allow a rectangular picture to be zoomed to a picture with dimensions not necessarily linearly related to the original rectangle. For example, the standard television picture could be zoomed to a smaller circular picture, similar to that produced by a `fish eye` lens.
The invention is not concerned merely with symmetrical shapes such as circular pictures and the system to be described is such that irregular patterns may be used as the zoomed shape, thus giving the ability to effectively turn one subject into another.
These effects themselves are known and are used already in the film industry and forms the basis of film production facilities for `credits` and background material.
The way in which these effects were previously produced was by means of for example a digital computer and a slow scan display system. In this prior art case the effect is produced on a frame by frame basis slowly and photographed at each step. Such an arrangement utilising photography on a frame by frame basis is relatively slow and not particularly suited to the television art.